So I now started modeling the brackets that will hold the heatsink. They will be connected to the platform and made so they can adjusted to slide back or forth.
The rectangular holes is for the nuts to slide in to. that way i can securely connect to the bracket with screws without making the threads in 3d. Another plus is that I can use locknuts.
A minus is that one side takes three hours to print with minimum infill... oh well.